Cyclic tests for unbonded steel plate brace encased in reinforced concrete panel or light-weight assembled steel panel

Abstract

Cyclic loading tests for the panel buckling-restrained brace (panel BRB) comprising an unbonded steel plate brace encased in a panel were carried out to investigate constructional details of a novel type light-weight assembled steel panel and to study reinforcement forms to improve the punching shear capacity of reinforced concrete panel. The effects of unbonded materials and gaps between the panel and the brace, reinforcements in concrete panels and weight of panels on the hysteretic behavior of panel BRBs, were mainly examined. Tests reveal that, compared with additional steel bars and ties, perforated steel channels used as reinforcements along the entire length of brace can prevent concrete panels from failure by punching shear. Residual flexural deformations appeared in some braces due to the gaps. The maximum axial compressive strength of each specimen significantly exceeds its yield strength due to strain hardening and frictional action. Lubricating greases in the steel panel BRBs are helpful to reduce the frictional action and to achieve satisfied hysteretic responses. All specimens achieved great ductility and energy dissipation capacity. The concrete panel in one specimen failed by punching shear and the other specimens failed due to tensile fracture of the braces. The weight of the assembled steel panel is about 30% that of the concrete panel and the hysteretic behavior of the steel panel BRBs matches that of the concrete panel BRBs. The panels that can be assembled and disassembled would be advantageous in inspecting and replacing the braces, as well as in reusing the panels.